Japanese Patent Publication No. 2001-212297 A discloses a prior art solenoid actuator of the hinged flapper type. The actuator includes an excitation coil wound around a coil bobbin, a core extending through the coil bobbin, and an armature extending along an axial direction of the coil. The core projects axially outwardly of the coil or the coil bobbin to provide a first pole end and a second pole end respectively at the opposite axial ends of the coil. The armature extends generally along the axial length of the coil and is pivotally supported to the core by means of a hinge spring with one end of the armature held close to the first pole end and with the other end held close to the second pole end. Upon energization of the coil, a magnetic attraction force develops to attract the one end of the armature towards the second pole end, causing the armature to pivot against the bias of the hinge spring. In this prior art solenoid actuator, a yoke is attached to the first pole end of the core for magnetically couple the armature to the core as well as for holding the hinge spring on the side of the core. Although the solenoid actuator makes the use of the full length of the coil to give a relatively long stroke to one end of the armature, it requires the yoke as well as the hinge spring as discrete parts in addition to the core, the coil, and the coil bobbin, eventually increasing a cost as well as inconvenience of assembling the solenoid actuator.